This is the Apple Watch's most important update yet

The Apple Watch Series 3 is the biggest and most consequential update to date. By adding LTE connectivity, Apple has delivered an upgrade that will completely change how you use the device.

Earlier iterations of the Apple Watch, and frankly, most other smartwatches, have been hamstrung by their dependency on your phone for data. By completely untethering the watch from your iPhone, it’s not a completely different story.

Prior to today’s unveiling there was some speculation as to whether Apple would significantly change up the design with Series 3. Not only did Apple not change the form factor of its watch, they managed to keep the case size nearly identical even with the additional LTE radio and SIM.

Image: KARISSA BELL / Mashable

The only difference is that the case is now slightly thicker. The company says it’s the equivalent of about two sheets of paper — but it’s not noticeable that I could see.

The most noticeable difference is the red dot on the Digital Crown, which doesn’t actually do anything other than let people know you’re wearing the latest Apple Watch, which is, of course, the point.

Speaking of colors, the Series 3 also comes in a few new finishes: a new shade of pinkish gold and a gray ceramic. Both are nice, if somewhat predictable, additions.

The new gold finish.

Image: karissa Bell/mashable

Gray ceramic.

Image: karissa Bell/mashable

Naturally, there are a load of new band styles and colors to go with the new watches. The woven nylon bands now come in new patterns, and there’s a new sport band made of soft nylon that promises that is much more adjustable than the existing sport band.

New bands and colors aren’t why you’re going to want to upgrade your Apple Watch, though. You’re going to upgrade because LTE connectivity completely changes what you can do with it.

The new sport band is more adjustable so it can fit closer to your wrist.

Image: karisa Bell/mashable

Yes, you can send text messages and make phone calls from your wrist even when your iPhone is at home. But it also means you can ask Siri to call you an Uber or a Lyft, stream music, and use any other Apple Watch-enabled app.

All this comes with one important caveat, though: You’ll have to fork over extra money to your carrier each month for your watch. And even though carriers tend to charge significantly less for smartwatch data, handing even a little more money over to telecom companies just plain sucks.

If you can get past that, though, there are other reasons to upgrade.

The latest version of watchOS also comes with new fitness tracking features, like the ability to track high intensity interval training. There’s also a built-in altimeter, which allows the watch and watch apps to better track your elevations — a huge update for skiers and snowboarders.

There are also a load of upgrades to the heart rate monitor. Now, the watch’s heart rate monitor can track your heart rate over time and, when paired with the Health app on the iPhone, surface all your past heart rate data.

As Apple pointed out during its keynote, this has big implications for how people monitor their health, since they can better track changes in their heart rate over time.